Al-Qaeda in the Arabian Peninsula has called on jihadists to target the United States, after Washington launched air strikes in Iraq against Islamist fighters calling themselves the Islamic State.
In a statement published on a Twitter account affiliated with the group's local affiliate, Ansar al-Shariah, AQAP said on Thursday: "... We declare our solidarity with our Muslim brothers in Iraq."
"We call on all Islamist groups ... to go after America as part of its plan for jihad, militarily, economically, or through the media."
"And we call on every Muslim, especially anyone who can enter America, to champion his brothers by going to war against America with everything he can."
The Reuters news agency said it could not immediately verify the authenticity of the Twitter account.
After its capture of the northern Iraqi city of Mosul in June, the Islamic State - previously named the Islamic State in Iraq and Syria - swiftly pushed to the borders of the autonomous ethnic Kurdish region, alarming Baghdad.
Last week it drew the first US air strikes in Iraq since the withdrawal of American troops in 2011.
Advice on drones
The group has been disowned by al-Qaeda, which considered it as too radical after it took control of large parts of Syria.
Nevertheless, the AQAP franchise offered their "brothers" in Iraq some advice on dealing with US drone strikes that the Yemen-based group has had to contend with for the past few years.
In its statement, AQAP advised its fellow Islamist fighters to be wary of spies "because they are the main factor in specifying targets," to be careful when dealing with telephones and internet networks, and to disperse in fields if there is a heavy concentration of planes.
"We reaffirm to our Muslim nation that we stand in one trench with our Muslim brothers in Iraq against the American Crusader and Iranian conspiracy," the statement said.
Earlier this week a top AQAP leader hailed the Islamic State group's seizure of swathes of Iraq.
A senior US official last month expressed concern over possible collaboration between bomb makers from Yemen and fighters in Syria, where the Islamic State group has also seized extensive territory in the rebellion against President Bashar al-Assad.